An internal combustion engine may include an engine block defining a plurality of cylinder bores, a crankshaft rotatably supported in the engine block, and pistons connected to the crankshaft and configured to reciprocate within the cylinder bores. Typically, each piston may include a skirt pivotally connected to the crankshaft, and a crown connected to a distal end of the skirt. A combustion bowl may be formed on an end face of the crown to receive injected fuel, and annular grooves may be formed in an outer surface of the crown to receive associated rings. A cooling passage may be annularly formed inside the crown, between the bowl and the cooling passage, to circulate engine oil that may cool the bowl.
During operation of the engine, fuel and air is combusted inside the cylinder bore (and inside the bowl), to generate heat and pressure that is turned into mechanical work. Over a period of time, carbon deposit may grow on the piston. For example, carbon deposit may grow on a bottom portion of the piston (and/or a top portion of the piston). For instance, carbon deposit may grow under the crown of the piston (and/or the crown). As the carbon deposit grows on the piston, the piston may become insulated and may be unable to reduce the temperature of the piston within a threshold amount of time. In other words, the piston may be unable to cool down within the threshold amount of time. Accordingly, as fuel and air continues to be combusted inside the cylinder bore, the temperature of the piston may continue to increase and the amount of time for the piston to cool down may increase. As a result of the increase of the temperature of the piston and the increase in the amount of time for the piston to cool down, the piston may be damaged. For example, a rim of the bowl of the piston may be damaged.
U.S. Patent Application Publication No. 20150345421 (hereinafter the '421 publication) is directed to a piston of an internal combustion engine. The piston may include a piston crown with annular grooves, a combustion chamber bowl, and a piston skirt with a pin bore to receive a pin. However, the '421 publication does not disclose monitoring carbon deposit growth on the piston.